Tor, the team behind the world's leading online anonymity service, known colloquially as the "dark net" or "deep web", has announced that it will develop a new anonymous instant messenger client, according to documents produced at the Tor 2014 Winter Developers Meeting in Reykjavík, Iceland.

The Tor Instant Messaging Bundle (TIMB) will do to instant messaging what the Tor network did for Internet browsing – that is, completely anonymise it, by routing it through a vast and unpredictable network of relays.

Tor has claimed that its new chat network will allow "people in countries where communication for the purpose of activism is met with intimidation, violence, and prosecution" to "avoid the scrutiny of criminal cartels, corrupt officials, and authoritarian governments."

Software such as TorChat and BitMessage already have significant userbases and smart advocates, but with the full weight of the Tor Launcher and team behind it, TIMB could be something else entirely.

Tor works by piling up layers of encryption over data, nested like the layers of an onion, which gave the network its original name, The Onion Router (TOR).

Tor encrypts data, including the destination IP address, multiple times and sends it through a virtual circuit made up of successive, randomly selected relays. Each relay decrypts a layer of encryption to reveal only the next relay in the circuit.

The final relay decrypts the innermost layer of encryption and sends the original data to its destination without revealing, or even knowing, the source IP address.